sinelaw/fresh · warning · io::Error (Unsupported)

Memory detection not implemented for this platform

Error message

Memory detection not implemented for this platform

What it means

total_memory_mb() reports the machine's total RAM so the editor can enforce process memory limits. Only Linux detection is implemented; on any other target OS the cfg(not(target_os = "linux")) arm returns io::ErrorKind::Unsupported. This is an explicit not-yet-ported error, not a runtime fault.

Solutions

Skip or degrade process memory limiting when total_memory_mb() returns Unsupported
Implement the platform arm using sysinfo/libc (host_statistics on macOS, GlobalMemoryStatusEx on Windows, sysconf on BSD)
Use a cross-platform crate such as the `sysinfo` crate for detection
Only call limit-setting code under #[cfg(target_os = "linux")]

Example fix

// before
let mem = total_memory_mb()?;
set_rlimit(RLIMIT_AS, mem)?;
// after
match total_memory_mb() {
    Ok(mem) => set_rlimit(RLIMIT_AS, mem)?,
    Err(e) if e.kind() == io::ErrorKind::Unsupported => log::info!("memory limits unavailable on this platform"),
    Err(e) => return Err(e),
}

Defensive patterns

Strategy: fallback

Validate before calling

#[cfg(not(target_os = "linux"))] let can_detect_memory = false;
#[cfg(target_os = "linux")] let can_detect_memory = true;

Try / catch

match total_memory_mb() { Ok(mb) => apply_limit(mb), Err(e) if e.kind() == io::ErrorKind::Unsupported => log::info!("limits unsupported here"), Err(e) => return Err(e.into()), }

Prevention

Gate platform-specific limit setup behind cfg attributes
Prefer std::thread::available_parallelism()/sysinfo crate over hand-rolled per-OS code
Add cross-platform CI to catch unported code paths early

When it happens

Trigger: Calling process_limits::total_memory_mb() (public) on macOS, Windows, BSD, or any non-Linux target. Also affects anything downstream that depends on memory limits being initialized on those platforms.

Common situations: Building/running the editor on macOS or Windows with process limits enabled; cross-platform test suites calling limit setup unconditionally.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

AI-assisted analysis of sinelaw/fresh@67894ca546 (2026-09-13). Data as JSON: /api/errors/225ad7a080115c8e. Report an issue: GitHub.

Appendix: source

Thrown at crates/fresh-editor-core/src/process_limits.rs:318

fn get_uid() -> u32 {
    unsafe { libc::getuid() }
}

/// System resource information utilities
pub struct SystemResources;

impl SystemResources {
    /// Get total system memory in megabytes
    pub fn total_memory_mb() -> io::Result<u64> {
        #[cfg(target_os = "linux")]
        {
            Self::linux_total_memory_mb()
        }

        #[cfg(not(target_os = "linux"))]
        {
            // TODO: Implement for other platforms
            Err(io::Error::new(
                io::ErrorKind::Unsupported,
                "Memory detection not implemented for this platform",
            ))
        }
    }

    #[cfg(target_os = "linux")]
    fn linux_total_memory_mb() -> io::Result<u64> {
        // Read from /proc/meminfo
        let meminfo = std::fs::read_to_string("/proc/meminfo")?;

        for line in meminfo.lines() {
            if line.starts_with("MemTotal:") {
                // Format: "MemTotal:       16384000 kB"
                let parts: Vec<&str> = line.split_whitespace().collect();
                if parts.len() >= 2 {
                    if let Ok(kb) = parts[1].parse::<u64>() {
                        return Ok(kb / 1024); // Convert KB to MB

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